Research | Concepts | Seismic Reflection Exploration

Copyright Kerry Key 2003

The seismic reflection method is the primary tool for offshore exploration. A survey ship releases high pressure explosions ("shots") from an air gun array. The pressure wave expands out form the shot location and forms reflections waves from the boundaries and layers of geologic structure. The reflected waves are then measured on hydrophones (underwater microphones) towed behind the ship on the sea surface. By knowing the time of the air gun shot and the time the waves reach the hydrophones, the layering and geologic boundaries of the subsurface can be reconstructed.

An example of a depth migrated seismic reflection profile from Gemini Prospect, Gulf of Mexico is shown below. The black and white area correspond to different layers within the seafloor. The brightest reflections are from a salt intrusion.

Reflection image courtesy of ChevronTexaco and WesternGeco.